1. Field of the Invention:
The present invention relates generally to agricultural seed planters, and more particularly to devices for delivering seed from the planter""s seed meters to the open seed furrows.
2. Description of Related Art:
It is well recognized that uniformity in the spacing of seeds in a seed furrow is essential for maximizing a field""s crop yield and thus enhancing the profitability of the farmer""s operation. Modern agricultural planters use various types of seed metering devices designed to select and discharge individual seeds at regular intervals, to ideally achieve this uniformity in seed spacing.
The various types of seed metering devices currently being used on agricultural seed planters can generally be divided into two categories on the basis of the seed selection mechanism employed, namely, mechanical or pneumatic. The commercially available mechanical meters include finger-pickup meters such as disclosed in U.S. Pat. No. 3,552,601, cavity-disk meters such as disclosed in U.S. Pat. No. 4,613,056, and belt meters such as disclosed in U.S. Pat. No. 5,992,338. Commercially available pneumatic meters include vacuum-type meters such as disclosed in U.S. Pat. No. 5,501,366, and compressed air meters. Other commercially available meters combine the seed selection mechanisms of both mechanical and pneumatic meters such as disclosed in U.S. Pat. No. 4,074,830.
Regardless of whether they are of the finger-pickup type, vacuum-disk type, cavity-disk type or belt-type, the seed meters typically are mounted just below the seed hopper at heights ranging from about eighteen to about twenty-four inches above the ground surface. As a result, planters employing such metering devices also require seed tubes to direct the seeds into the open seed furrow after the singulated seeds are discharged from the seed meter.
It has been found that the use of seed tubes to deliver the seeds to the seed furrow have a negative effect on the uniformity of seed spacing in the furrow. This is due to the fact that some of the seeds descend through the seed tube rapidly, substantially in a free-fall through the entire length of the seed tube, while other seeds contact the walls of the seed tube more frequently as they descend through the seed tube, even to the point of ricocheting between opposite sides of the seed tube. These differences in the degree of contact with the seed tube lead to differences in the rates at which the seeds travel through the tube. In fact, it has been shown that on occasion a later-discharged seed from the seed meter will actually pass an earlier-discharged seed as both descend through the seed tube.
Several factors contribute to this problem. As an agricultural planter traverses a field, surface irregularities in the field lead to momentary jostling, vibration or other positional shifting of the planter components, including the seed tubes. Irregularities among the seeds themselves may be a factor as well. In any event, the uniformity at which seeds enter the seed tube after exiting the seed meter is typically not present as the seeds exit the seed tube. Further, although each seed tube performs the useful function of guiding its seeds toward the open furrow, the differences in velocities at which the seeds exit the seed tube toward the ground have an adverse effect on uniformity of seed spacing in the furrow.
Thus, there is a need in the agricultural industry for an apparatus and method for controlled delivery of the seed between the seed meter and the open furrow that improves seed placement accuracy within the open furrow at the desired seed spacing thereby improving crop yield and the efficiency and profitability of farming operations.
A seed dispensing apparatus and method for controlled delivery of seeds from an agricultural planter""s seed meter to an open furrow. The apparatus includes a conveyor support structure adapted for receiving individual seeds discharged by a seed metering device of an agricultural planter. The conveyor support structure includes a first end positioned near the seed metering device to receive seeds metered individually and in a sequence therefrom. A second end of the conveyor support structure is positioned proximate an open furrow in an agricultural field for movement along the furrow as the agricultural planter traverses the field. The apparatus further includes a seed conveyor mounted movably relative to the conveyor support structure. The seed conveyor is operable at a controlled conveyor speed to transport the seeds, in the sequence in which they are received from the seed meter, at the controlled conveyor speed from the first end toward the second end of the conveyor support structure. The conveyor further is operable to serially release the seeds proximate the second end of the conveyor support structure to dispense the seeds in sequence into the open furrow.
The conveyor support structure advantageously is provided as a housing, with an opening at the first end to receive the seeds from the seed meter, and an opening at the second end to dispense the seeds into the furrow. The housing, confines the seeds to more positively ensure their travel with the conveyor, and substantially at the controlled conveyor speed until they are dispensed.
In one preferred form, the seed conveyor includes an endless belt and a plurality of evenly spaced-apart flights extended outwardly from the belt. Each pair of adjacent flights cooperates with the belt to provide a seed compartment. At the first end, seeds are sequentially loaded into the compartments, one seed into each compartment. As the compartments travel from the first end to the second end for dispensing, walls of the housing cooperate with the belt and flights to retain each seed within its associated compartment until the compartment emerges from the housing at the second end, whereupon the seed is dispensed to the furrow.
Preferably the second end of the seed dispensing device is located near a top of the open furrow. If desired, the dispensing device incorporates a seed guide extending from the second end toward a bottom of the furrow, to further guide each seed as it descends toward the bottom of the furrow.
In an alternative approach, the seed conveyor includes two endless belts, juxtaposed to provide a conveyance path along which respective segments of the belts face one another in substantially uniform spaced-apart relation. The conveyance path extends from the first end to the second end, and along the conveyance path the opposing belt segments are driven in the same direction and at the same controlled conveyor speed. The distance between the opposed belt segments is less than the size (diameter or equivalent approximation) of the seeds. Consequently the seeds are maintained between the opposed belt segments by belt elasticity and friction as they are carried from the first end to the second end for dispensing.
The seed conveyor, whether a single flighted belt or a pair of confronting belts as just described, can be driven by a pulley operably coupled to the seed meter, with result that the controlled conveyor speed is governed by the seed meter speed. This arrangement advantageously assures that a uniform dispensing of seeds from the seed meter results in a uniform spacing of seeds along the seed conveyor. This arrangement also more positively ensures a one-to-one relationship of seeds and compartments, when the seed conveyor is provided as a single, flighted belt.
In an alternative arrangement, the drive pullies of the seed conveyor can be driven independently of the seed meter, such as by being operably coupled to an independently driven drive shaft or the lee. In this way, the spacing of the seeds could be momentarily increased or decreased depending on ground speed independent of the dispensing speed of the seed meter.
According to an alternative form of the invention, a seed meter and seed delivery apparatus are provided in combination. The seed delivery apparatus is adapted to receive individual seeds discharged from the seed meter, and to controllably convey the individually dispensed seeds to an open furrow. The seed delivery apparatus comprises a housing in comnmunication with the seed meter to receive the individually discharged seeds. The housing is adapted to be operably supported by a row unit frame of an agricultural planter, and has an open end terminating near the soil surface in substantial alignment with the open furrow. A seed conveying assembly is disposed in the housing, and adapted to individually convey the individually discharged seeds through the housing at a substantially constant predetermined velocity toward the open end of the housing for a depositing of the seeds into the open furrow.
Further in accordance with the present invention, there is provided an improved agricultural seed planter having a main frame operably supporting a plurality of adjacently spaced row units, each of the row units having a row unit frame supporting a seed hopper, a seed meter adapted to discharge individual seeds at regular intervals, and a seed delivery device adapted to receive the individual seeds discharged from the seed meter and to convey the individually discharged seeds at a controlled conveyor speed to a location near an open furrow for dispensing the seeds into the furrow.
Thus in accordance with the present invention, the seeds associated with a given row unit are received individually and in a sequence from their associated seed meter, conveyed at a controlled conveyor speed to a location proximate an open furrow, then released into the furrow in the same sequence, as the agricultural planter moves forward. This ensures a more even spacing between adjacent seeds, improving the crop yield and enhancing the efficiency of the farming operation.